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HELOC Calculator

Enter your home’s value, your mortgage balance and the lender’s combined loan-to-value limit to see the credit line you could get. Then enter how much you plan to draw, the rate and the draw and repayment periods to see the interest-only payment now and the larger payment once repayment begins.

Quick examples
$
$
%

Most lenders allow 80–90% of the home’s value across all loans.

$

Assumed drawn at the start and kept out for the whole draw period.

%

HELOC rates are variable; this holds today’s rate fixed.

years
years
Your numbers stay in your browser. They are never uploaded.
Interest-only payment (draw period)$354.17
Payment in the repayment period
$433.91
Increase when repayment starts
$79.74
Credit line at your CLTV limit
$90,000.00
Unused credit
$40,000.00
Interest during the draw period
$42,500.00
Interest during repayment
$54,138.79
Total interest
$96,638.79
Principal
$50,000.00
What you pay over the life of the line
  • Principal
  • Draw-period interest
  • Repayment interest

Year by year

YearMonthly paymentPrincipalInterestBalance

Saved setups

Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.

    Your recent calculations

    Results you calculate here are kept on this device so you can come back to them.

      Also free on iPhone and Mac

      Formula

      Credit line = home value × CLTV limit − mortgage balance
      Interest-only payment = amount drawn × rate ÷ 12
      Repayment payment = balance × r ÷ (1 − (1 + r)^−n), with r = rate ÷ 12 and n = repayment years × 12
      Interest in the draw period = interest-only payment × draw months

      How to use it

      1. Enter your home value, mortgage balance and the lender’s CLTV limit.
      2. Enter how much you expect to draw and the current rate.
      3. Enter the draw period and repayment period from the offer — 10 and 20 years is common.
      4. Compare the interest-only payment with the repayment payment and plan for the jump.

      Worked examples

      $50,000 drawn at 8.5% with a 10-year draw period and 20-year repayment, on a $400,000 home with $250,000 owed

      Interest-only payment (draw period)
      $354.17
      Payment in the repayment period
      $433.91
      Increase when repayment starts
      $79.74
      Credit line at your CLTV limit
      $90,000.00
      Unused credit
      $40,000.00
      Interest during the draw period
      $42,500.00
      Interest during repayment
      $54,138.79
      Total interest
      $96,638.79

      $100,000 drawn at 7.75%, 10-year draw then 15-year repayment, 90% limit on a $600,000 home with $350,000 owed

      Interest-only payment (draw period)
      $645.83
      Payment in the repayment period
      $941.28
      Increase when repayment starts
      $295.44
      Credit line at your CLTV limit
      $190,000.00
      Interest during the draw period
      $77,500.00
      Interest during repayment
      $69,429.64

      $24,000 at 9% with a 5-year draw and 10-year repayment

      Interest-only payment (draw period)
      $180.00
      Payment in the repayment period
      $304.02
      Increase when repayment starts
      $124.02
      Credit line at your CLTV limit
      $90,000.00
      Interest during the draw period
      $10,800.00
      Total interest
      $23,282.62

      How a HELOC works

      During the draw period you can borrow, repay and borrow again up to the limit, and many lenders require only the interest each month. When the draw period ends, the line closes and the balance is repaid with principal and interest over the repayment period. Some HELOCs instead require the whole balance at the end of the draw period, so read the terms.

      This calculator assumes you draw the full amount at the start and pay only interest until repayment begins, which shows the largest likely interest cost.

      Variable rates and payment shock

      Most HELOC rates are variable, usually the prime rate plus a margin, so the payment moves with rates. Each 1 percentage point on a $50,000 balance changes the interest-only payment by $41.67 a month. Under current US federal rules, HELOC interest is deductible only if you itemize and use the money to buy, build or substantially improve the home that secures it. This is an estimate, not a loan offer or tax advice.

      Questions people ask

      What is the payment on a $50,000 HELOC?

      At 8.5%, $354.17 a month interest-only during the draw period. Once a 20-year repayment period starts it rises to $433.91 a month.

      How much is the interest-only payment on a $100,000 HELOC?

      Balance × rate ÷ 12. At 8% that is $666.67 a month; at 7.75% it is $645.83.

      How much does a HELOC payment go up after the draw period?

      It depends on the repayment term. $100,000 at 7.75% goes from $645.83 interest-only to $941.28 a month over a 15-year repayment period — $295.44 more.

      How big a HELOC can I get?

      Home value × CLTV limit − mortgage. A $400,000 home with $250,000 owed at an 85% limit allows a $90,000 line.

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